<!DOCTYPE html>
<html>

<meta charset="utf-8">
<script>
    function tanchuang() {
        alert("hello,world");
    }
</script>

<body>

    <select id="abc">
  <option value="下拉框01">北京</option>
  <option value="下拉框02">上海</option>
  <option value="下拉框03">广州</option>
  <option value="下拉框04">深圳</option>
</select>

    <input name="一个弹窗" type="button" onclick="tanchuang()" value="网页弹窗" />

</body>

</html>